The role of immune complexes in the pathogenesis of disease.

Circulating antigen-antibody complexes are incriminated in the pathogenesis of auto-immune and inflammatory disease, and more recently malignancy. Extensive knowledge of the immunopathological reactions has evolved from from the study of experimental serum sickness in animals and of the potential aetiological agents (e.g. viruses) from spontaneous immune complex diseases in animals. Numerous techniques, both direct and indirect, have now been described to identify immune complexes in serum, though no single technique will identify regularly immune complexes in all clinical situations, nor will it demonstrate the pathogenicity of the immune complex in a given patient. Human disorders with a definite immune complex basis (glomerulonephritis, systemic lupus erythematosus, rheumatoid arthritis) and others with a possible immune complex basis (e.g. cutaneous vasculitis, are presented. Management of immune complex disorders is based on removal of the initiating agent if known (e.g. infection, drug, malignancy) or the use of non-specific anti-inflammatory therapy. Specific immunotherapy, in practice and theory, is discussed.